Means for adjusting the angular relation between a workpiece
to be ground and a tool

ABSTRACT

(L.H.) GAGE HEADS (43, 44) AND GEERATES A SIGNAL WHEN THE DIFFERENCE VARIES BY MORE THAN A PREDETERMINED AMOUNT. COMPENSATION IS EFFECTED BY DEFLECTING THE APPROPRIATE WHEEL SPINDLE BEARING SUPPORT (41 OR 41&#39;&#39;) IN A FORWARD DIRECTION AS A SEPARATE FORCE APPLYING MEANS (49, 49&#39;&#39;) ARE PROVIDED AT EACH END OF THE WHEEL SPINDLE (18) FOR THAT PURPOSE. AN AUTOMATIC TAPER COMPENSATOR IS USED TO MAINTAIN A PARALLEL RELATIONSHIP BETWEEN THE AXIS OF A WIDE GRINDING WHEEL OR MULTIPLE GRINDING WHEELS (22-26) AND THE CENTERLINE OF A CYLINDRICAL WORKPIECE (W) ON A GRINDING MACHINE. TWO GAGE HEADS (43,44) ARE AUTOMATICALLY ADVANCE DURING THE GRINDING CYCLE AT THE EXTREME ENDS OF THE WORKPIECE PORTIONS BEING GROUND. A DIFFERENTIAL CIRCUIT (48) DIRECTLY COMPARES THE VOLTAGE OUTPUT OF THE RIGHT HAND (R.H.) AND THE LEFT HAND

R. E. PRICE Re. 28,082 USTING THE ANGULAR RELATION BETWEEN A WORKPIECE OBE GROUND AND A TOOL Original Filed Jan. 16, 1970 July 23, 1974 MEANSFOR ADJ 4 Sheets-Sheet 1 '00 RH TAPER COMPENSATION IOI MAIN HYDI SUPPLYLHv TAPER COMP IP SOL GAGE AUVANCE MAIN AIR OR HYDI SUPPLY INVENTORRALPH E. PRICE BY KW A ORNEY Re- ULAR RELATION BETWEEN A WORKPIECE O BEGROUND AND A TOOL July 23, 1974 R. E. PRICE MEANS FOR ADJUSTING THE ANGOriginal Filed Jan. 16, 1970 4 Sheets-Sheet 2 FIG. 2

INVENTOR PRICE BY ATTORNEY RALPH E.

July 23, 1974 p Re. 28,082

TING THE ANGULAR RELATION BETWEEN A WOBKPIECE o BE GROUND AND A TOOLMEANS FOR ADJUS Original Filed Jan. 16, 1970 4 Sheets-Sheet 5 I 0 N n 20to J8 m: Q 5mm 2052528 E3 2952528 :1 0.3 2D 8 W 8 o 630 855.51 50558 8;A was 93 o] mm: 52% 5228 2:5 Q28 U 0' K A 222E 2 2: E28 +2 .5

26 w 20 zQEmzwaES INVENTOR RALPH E. PRICE BY MW ATTORNEY mmm mm m# .5328$20 rm mo I 55 so in R. E. PRICE Re. 28,082 MEANS FOR ADJUSTING THEANGULAR RELATION BETWEEN A WORKPIECE July 23, 1974 O BE GROUND AND ATOOL 4 Sheets-Sheet 4.

Original Filed Jan. 16, 1970 .rll 2 mm QE Emma @200 :4

E H P L A R ATTORNEY Q xood 852% m 1 M xsssE 3 5 mm A,

United States Patent 28,082 MEANS FOR ADJUSTING THE ANGULAR RELA- TIONBETWEEN A WORKPIECE TO BE GROUND AND A TOOL Ralph E. Price, Waynesboro,Pa., assignor to Landis Tool Company Original No. 3,690,072, dated Sept.12, 1972, Ser. No. 98,807, Jan. 16, 1970. Application for reissue Feb.1, 1973, Ser. No. 328,664

Int. Cl. B2411 49/04 U.S. Cl. 51-165 R Claims Matter enclosed in heavybrackets II] appears in the original patent but forms no part of thisreissue specification; matter printed in italics indicates the additionsmade by reissue.

ABSTRACT OF THE DISCLOSURE An automatic taper compensator is used tomaintain a parallel relationship between the axis of a wide grindingwheel or multiple grinding wheels (2226) and the centerline of acylindrical workpiece (W) on a grinding machine. Two gage heads (43, 44)are automatically advanced during the grinding cycle at the extreme endsof the workpiece portions being ground. A differential circuit (48)directly compares the voltage output of the right hand (R.H.) and theleft hand (L.H.) gage heads (43, 44) and generates a signal when thedifference varies by more than a predetermined amount. Compensation iseffected by deflecting the appropriate wheel spindle bearing support (41or 41') in a forward direction, as separate force applying means (49,49) are provided at each end of the wheel spindle (18) for that purpose.

BACKGROUND OF THE INVENTION 1. Field Of The Invention This inventionrelates to an improved method and apparatus for preventing a taper frombeing formed on a workpiece, which is being ground on a multiplegrinding wheel machine. The invention also has application on wide wheelgrinding machines. In multiple or wide wheel cylindrical grindingmachines, it is very important to maintain a parallel relationshipbetween the axis of the workpiece and the axis of the grinding wheel(s).Otherwise, the workpiece can be ground with a taper, i.e., one end ofthe workpiece is ground oversize in relation to the other. It isdesirable that adjustments be made to the relative positions of thewheel(s) and workpiece(s) during the grinding cycle in order to providefinished pieces which are ground to the same tolerance over the entirelength thereof. This invention has particular application in grindingworkpieces such as automotive crankshafts wherein the main bearings areground on an automative machine having multiple wheels, spaced accordingto the bearings.

2. Description Of The Prior Art Prior to this invention, gaging meanswere provided for measuring spaced diameters on a workpiece. Facilitieswere provided to stop the grinding operation if one of the diameters wasground to a low limit before the other diameter had been ground to ahigh limit. The taper was then corrected by adjusting a swivel table aslight amount to compensate for the measured taper. An example of thismethod was covered in the Pheil US. Pat. No. 3,097,454, granted July 16,1963. This method is used on manual machines and would not besatisfactory for automatically-operated machines.

In the Haisch US. Pat. No. 3,271,910, granted Sept. 13, 1966, a parallelor a predetermined angular position between the axis of a grinding wheelspindle and ICC the axis of the workpiece was controlled automatically.In the only operative embodiment disclosed in this patent, the headstock(or tailstock, but not both) was displaced to compensate for anyresulting taper. This approach has the drawback that the movement of theheadstock (or tailstock) can interfere with the work rest positionedadjacent thereto. It should also be noted that if any over-correctionoccurs, contact between the grinding wheel and the workpiece would belost, since the headstock (or tailstock) then had to be retracted. Thishas the disadvantage of disturbing the spatial relationship between theworkpiece and the wheel, causing further gaging problems.

SUMMARY OF THE INVENTION In accordance with the invention, a multiple orwide Wheel grinding machine is provided for grinding axially spacedportions of a workpiece. The machine includes a work support forsupporting the workpiece and the grinding wheel support including aspindle for supporting one or more rotatably mounted grinding wheels.Means are provided to effect a relative transverse feeding movementbetween the wheel spindle and the workpiece support to perform agrinding operation. At least two electrical size signals are generatedfrom spaced portions on the workpiece during the grinding cycle. The twosignals are compared directly and a third signal is generated when thedifference between the signals exceeds a predetermined value. The thirdsignal actuates means for deflecting the wheel support to move thecorresponding grinding wheel toward the workpiece.

In the preferred embodiment, separate and independent means are providedat spaced portions of the grinding wheel, to displace one or the otherof the spindle supports in a transverse direction. In order tofacilitate the deflection of the spindle supports, the supports are inthe form of cantilever arms which can be deformed in a forward directiontoward the workpiece.

It is, therefore, an object of the present invention to control aparallel relationship between the axis of the wheel spindle and the axisof the workpiece automatically.

Another object is to provide a control device which directly comparesthe voltage output from two gages to each other and generates a tapercompensating signal in response thereto.

Another object is to remove all compensation from the workpiece, whichenables the original setting of the headstock, tailstock, work rests,and the gage heads to be undisturbed during the complete grinding cycle.

Another object is to maintain a parallel relationship between the axisof the wheel spindle and the axis of the workpiece, without interferingwith the support[of] or pressure from a work rest.

Another object is to provide a means for compensating for any taperautomatically, without losing contact between the grinding wheel and thesurface of the workplece.

Another object is to enable any over-compensation to be corrected byeffecting movement of the opposite taper compensating mechanism, withoutlosing contact between the grinding wheel and the surface of theworkpiece.

Another object is to provide means to reset the position of the grindingwheel spindle to its original parallel position at completion of eachgrinding cycle automatically.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a multiplewheel grinding machine, embodying the present invention, and showingtaper compensation mechanisms for advancing either end of the grindingwhee] spindle, the visual read- DESCRIPTION OF THE PREFERRED EMBODIMENTSReferring now to the drawings, in FIG. 1, there is illustrated the planview of a grinding machine, generally designated by the numeral 10,having a bed 11, which supports a wheel support 12 and a work support13. The wheel support 12 carries the spindle bearings 16 and 17, whichsupport the rotatable spindle 18. The spindle bearings are retained in aspaced relation by means of RH. and L.H. clamps, l9 and 20, which arepivotably mounted, but secured to the front of the wheel support 12,through fasteners 21. Grinding wheels 22, 23, 24, 25, and 26 are carriedin a spaced relation to correspond to the portions of the workpiece W tobe ground, by means of spacers 27, 28, 29, 30, 31

and 32, which are locked in position by wheel center rings 33 and 34.

The workpiece W is rotatably supported by the headstock and tailstockwork centers 36 and 37 in a conventional manner. The headstock 38 andthe tailstock 39 are longitudinally positioned and locked to the worksupport 13, and the work support 13 is manually positioned to align theworkpiece portions with the spaced grinding wheels 22-26.

The front portion of the wheel support 12 includes wheel spindlesupports 41 and 41' which are longitudinally spaced to form the rearsupport for the spindle bearings 16 and 17 at the respective locations.As shown in FIG. 2, the wheel spindle support 41 is connected to thewheel support 12 at its lower end, but is unsupported at its upper end,the wheel support 41' is formed in a similar manner. The supports 41 and41 act as cantilever arms which can be deflected to change the angularposition of the wheel spindle 18 with respect to the workpiece W. Theappropriate support 41 or 41' is deflected automatically during a dwellin the grinding cycle to insure a parallel relationship between the axisof the wheel spindle 18 and the axis of the workpiece W prior toreaching size.

An electronic grinding gage system 42 consists of two gage heads 43 and44 having readout dials 46 and 47 which receive signals fromconventional probe members or transducers 45 and 45' and also directs asignal to a differential comparator circuit 48, which compares allreadings directly through a continuous plus or minus reading from anormal zero setting as indicated by a differential dial 50, describedmore fully hereinafter. (The gage system 42 is similar to the electronicgage Model 135B- 79 [(-1 shown in a catalogue of Federal ProductsCorporation, 1144 Eddy Street, Providence, RI. 02901.) The differentialcomparator circuit 48 includes two oscillators (not shown) whichtransmit signals through linear variable dilferential transformers tothe transducers 45 and 45'. The transducers 45 and 45 send voltagesignals back to the differential comparator circuit 48, the voltages ofwhich are a function of the position of the transducers. The signals aredirectly compared in the differential comparator circuit 48, and ifthere is a differential between the voltages which exceeds apredetermined amount, one of the two relays (not shown) within thedifferential comparator circuit 48, is energized. A first of the relayshas a contact CR1 and a second of the relays has a contact CR2 (see FIG.2). This circuit 48 is used to make taper corrections by advancing therespective end of the wheel spindle 18 automatically to compensate forany undesired taper between the ends of the workpiece W, when thetolerance limits are exceeded.

Each end of the spindle 18 is advanced by the movement of a tapercompensator assembly 49 and 49', to compensate for the oversize diameterportion. The taper compensation assemblies 49 and 49' are secured toeach side of the wheel support 12, as shown in FIG. 1.

The RH. and L.H. taper compensating mechanisms are identical, therefore,only the RH. assembly 49 will be described. The right hand end of thewheel spindle 18 is advanced when the diameter of the right hand end ofthe workpiece W exceeds the tolerance over the lft hand diameter. Theforward movement is effected by movement of a piston 51, within ahydraulic cylinder 52, which is [s] secured to a R.H. housing 53,through an adaptor plate 54. The R.H. housing 53 houses a bushing[busing] 56, which supports a slidable plunger 57. The plunger 57 is inthreaded engagement with a pinion nut 58. The outer teeth 59 of thepinion nut 58 are in mesh with the teeth of a rack member 61 which issecured to a piston rod 62 of the piston 51. A threaded portion of thepinion nut 58 is in threaded engagement with the internal threads of thebushing 56, to provide a fine advance movement of the plunger 57, bymeans of differential threads.

The bushing 56 includes a vertical slot 63, as shown in FIG. 2, whichenables a key 64 to be secured to the plunger 57, to prevent the plunger57 from rotating when the pinion nut 58 is rotated. The sides of theslot 63 also provide means to limit the total amount of movement of theplunger 57 in either direction.

Movement of the piston rod 62 effects movement of the rack member 61,and the pinion nut 58 is rotated, which advances the pinion nut 58 tothe left, as shown in FIG. 2. The plunger 57 is retracted to the rightrelative to the pinion nut 58. However, by varying the threads per inchon the nut 58 and the plunger 57, it is possible to advance the nut 58at a faster rate than the plunger 57 retracts, thereby giving theplunger 57 an absolute advance to the left (FIG. 2) at a fine ratethrough differential threads. For example, the nut 58 may have 8 threadsper inch, and the plunger 10 threads per inch. Therefore, the plunger 57is advanced against a pressure post 66, that is secured to the wheelspindle support 41. Movement of the plunger 57 deflects the wheelspindle support 41 a slight amount and the RH. bearing 16 and the RH.end of the spindle 18 are advanced until the signals from the gage heads43 and 44 come within the allowed tolerance as determined by thedifferential comparator circuit 48. The normal fine feed rate is theninitiated and continues until size is reached.

It should be understood that the control means which effects theoperation of the taper compensating mechanisms 49 and 49' are notactuated until after the wheel support 12 has been advanced by any ofthe conventional means. The gage heads 43 and 44 are not advanced toengage the workpiece diameters until the diameter of the workpiece W hasbeen rough ground. This method is conventional and prevents the gageheads 43 and 44 from being damaged by the rough surface of an ungroundworkpiece.

OPERATION The grinding wheels 22-26 or a single wide wheel (not shown)are advanced by a digital feed system which effects movement of thewheel support 12 for predetermined distances and at predetermined rates,after the workpiece W has been properly positioned in alignment with thegrinding wheels 2226, and after the headstock 38 has started therotation of the workpiece W. A feed system of this type is disclosed inco-pending application of Price et al. Ser. No. 45,829, filed on June12, 1970, entitled Feed Rate and Positioning Control System for aMachine Tool," assigned to Landis Tool Co., which is expresslyincorporated herein.

A sequence control counter disclosed in the above patent applicationdetermines the rate of infeed, the end points, and the dwell periodsduring the grinding operation, by controlling the rate and the number ofpulses directed to the electro-hydraulic pulse motor. The pulse motoradvances the grinding wheels 22-26 transversely at preselecteddistances, until a size signal is obtained by means of the gage heads 43and 44.

The grinding wheels are advanced at a rapid infeed rate, until a loadcontrol relay (not shown) is deenergized by contact between the grindingwheels 22-26 and the workpiece W. This reduces the infeed rate of thegrinding wheels 2226 to a first grinding feed rate. The work rests 67and 68 are advanced to compensate for the resultant forces from thegrinding wheels 2226, to prevent deflection of the workpiece W in aconventional manner. The grinding feed rate continues until a dwellperiod is effected.

The gage heads 43 and 44 are then advanced to a position as shown inFIG. 1 in the following manner. A gage advance solenoid 1P SOL isenergized which shifts a control valve 79 to the left, and fluidpressure is directed through a line 80 to the valve 79 and to the headend of the hydraulic motors or cylinders 81 and 82 through lines 83,[83a] 83A and [83b] 83B. Flow control valves 86 and 87 are included inthe lines [83a] 83A and [83b] 83B, respectively, to control theoperating speed of pistons 88 and 89, by throttling the pressure and byallowing free flow of the returning fluid. Fluid pressure from the lines83, 83A, and 83B advances the pistons 88 and 89, which advance the gageheads 43 and 44, respectively, against the end portions of the workpieceW. The lines 90 and 90A direct the fluid being exhausted from the rodend of the cylinders 81 and 82 through the valve 79 and to a drain 85.

The wheel support 12 is retracted a small amount at the end of a firstdwell period, until the, counter is equal to the number set on the resetswitches (not shown). The grinding wheels 22-26, are advanced after asecond dwell period and a second feed rate is effected which continuesuntil either of the No. 2 gage contacts on the dial 46 or 47 aretripped, to effect the third dwell period.

Taper compensation will be effected automatically during the third dwellperiod, by the energization of the RH. or L.H. taper compensationsolenoids HA SOL or llHA SOL, respectively, if the comparator circuit 48indicates a predetermined difference between the RH. and the L.H.portions of the workpiece W.

In the case of right hand compensation, the contact CR1 in a line 69(FIG. 2) is closed by energization of its associated relay (not shown)in the comparator circuit 48. A circuit is completed to a converter 72which converts the voltage to a logic level, and through a SchmittTrigger 74 which squares the pulse waves in a conventional manner, toprovide a signal that the RH. diameter is over the tolerance range.(Left hand compensation is similarly effected through closure of contactCR2 in a line 71 which completes a circuit through a converter 73 and aSchmitt Trigger 75.)

When the taper compensation switch S810 is in the ON position, tapercompensation will be effected to advance the RH. end of the wheelspindle 18. This occurs when the signal from the comparator circuit 48determines that the diameter of the RH. portion of the workpiece W asmeasured by the transducer 45 of the RH. gage head 43, exceeds theallowable tolerance over the diameter being measured by the transducer45' of the L.H. gage head 44.

Referring to FIGS. 3A and 3B, the solenoid 10HA SOL is energized when asignal from an expander 91 is directed to an AND gate 92 through a line93 and the AND gate 92 directs a signal to an AND gate 97 through a line94. A signal is directed from the AND gate 97 to an output converter 98through a line 99. The output converter 98 converts the d-e voltagesignal to an a-c voltage signal and energizes the solenoid 10HA SOL,which is protected by conventional fuses (unnumbered).

The energization of the solenoid 10HA SOL shifts a control valve 100 tothe right (FIG. 1). Main pressure from a hydraulic source directshydraulic fluid from a line 101 through the valve 100, and through aline 102, which connects the valve 100 to the head end of the hydrauliccylinder 52. A flow control valve 103 is included in the line 102 tocontrol the operating speed of the piston 51 within the cylinder 52 bythrottling the fluid pressure and by allowing free flow of the returningfluid when the piston 51 is reset. The piston 51, the piston rod 62, andthe rack member 61 which are in mesh with the outer teeth 59 of thepinion nut 58, are advanced. This movement effects rotation of the nut58 which advances to the left (FIG. 2), and the plunger 57 is retractedto the right at a slower rate. Therefore, the pinion nut 58 drives theplunger 57 against the post member 66, at a fine feed rate, whichdeforms or deflects the wheel spindle support 41, to effect the forwardmovement of the RH. end of the wheel spindle 18.

Referring now to FIG. 1, it should be understood that the line 104directs the fluid being exhausted from the rod end of the cylinder 52through the valve 100, and to a line 105 which is connected to a drain106.

Movement of the plunger 57 continues, until the comparator circuit 48determines that the signals returning from the transducers 45 and 45 arewithin a specified limit, as visually indicated by the differential dial50. The contact CR1 is opened and solenoid 10HA SOL is then deenergized,whereupon the control valve 100 is returned to its normal position byspring pressure.

The fine feed rate is started at completion of the third dwell period.The grinding wheels 2226 are advanced at a slow rate until either of theNo. 3 gage contacts, as shown on the readout dials 46 and 47 (FIG. 1)are tripped. The fourth dwell period is effected and a sparkoutoperation is effected which continues until size is obtained. The wheelsupport 12 is retracted in a conventional manner when size is reachedand the RH. taper compensating assembly 49 is reset. The reset movementis effected by the energization of the solenoid 10HB SOL, which occurswhen the RH. compensation flip-flop 107 (FIG. 3A) is reset. This occurswhen the line 108 directs a signal to the ac converter 109, whichconverts the dc voltage signal to an ac voltage signal, and energizesthe RH. compensation reset solenoid 10HB SOL.

The R.H. compensation flip-flop 107 is reset when a signal from theexpanders 76 and 77 are directed to the AND gate 78 which directs asignal to the flip-flop 107 through a line 84, following a delay afterthe grinding cycle is completed. The flip-flop 107 is also reset shouldthe footstock 39 be retracted, as an expander will provide a signal tothe AND gate 78 which is connected to the flip-flop 107 through the line84.

The energization of the solenoid IOHB SOL shifts the control valve(FIG. 1) to the left, and hydraulic fluid is directed from the line 101through the valve 100, and through the line 104, to the rod end of thecylinder 52. The piston 51 and the piston rod 62 are reset and the rackmember 61 rotates the pinion nut 58 to retract the plunger 57 to thereset or original posi tion. The axis of the wheel spindle 18 isreturned to its normal free position which is parallel to the axis ofthe workpiece W.

It should be understood that the operation of the L.H. tapercompensation assembly 49 as shown in FIG. 1, is effected in a similarmanner, should the comparator circuit 48 determine that the diameter ofthe L.H. portion of the workpiece W, as measured by the transducer 45'of the L.H. gage head 43, exceeds the allowable tolerance over thediameter being measured by the transducer 45 of the RH. gage head 43.The L.H. compensation advance solenoid llHA SOL is energized, and thecontrol valve 111 is shifted to the right. Fluid pressure is directedthrough the lines 101 and 101A, through the valve 111 to a line 112,which is 7 connected to the head end of the cylinder 52'. A flow controlvalve 113 is included in the line 112 to control the operating speed ofthe piston 51' within the cylinder 52' by throtling the fluid pressureand by allowing free flow of the returning fluid when the piston 51' isreset. It should be understood that the line 114 directs the fluid beingexhausted from the rod end of the cylinder 52' through the valve 111, toa line 116 which is connected to the line 105 and drain 106.

Taper compensation is then effected in the manner as previouslydescribed, ad the L.H. side of the wheel spindle support 41' isdeflected to advance the L.H. end of the wheel spindle 18, until thesignals returning from the transducers 45 and 45' are within specifiedlimits. Fine feed is then started and the wheel support 12 is advancedat a fine feed rate until size is reached.

The wheel support 12 is retracted in a conventional manner following adelay after size is reached, and the L.H. compensating reset solenoidllHB SOL is energized. The control valve 111 is shifted to the left, andhydraulic fluid from the lines 101 and 101A is directed through thevalve 111 and to the rod end of the cylinder 52, through the line 114.The piston 51 is reset, and the plunger 57' is retracted to its resetposition in preparation for grinding the next workpiece W.

The control circuit in FIG. 3B for L.H. taper compensation is similar toFIG. 3A for R.H. taper compensation, and like elements have been givenlike numerals with a prime designation.

It should be understood that the fine feed rate is stopped at any time,should the comparator circuit 48 determine that the difference betweenthe RH. and L.H. portions of the workpiece W indicates a taper. A signalis directed from the AND gate 92 to an AND gate 118 through a line 119when a signal for R.H. compensation is generated. A signal from an ANDgate 92' directs a signal through a line 121 to the expander 122 and tothe AND gate 118 when a signal for L.H. compensation is generated. TheRH. or L.H. compensation is otherwise eflfected as previously stated.

While this invention is described in detail with reference to automaticmeans for maintaining a parallel relationship between the grinding wheelaxis and the centerline of a cylindrical workipece W, it should beunderstood that the operation of the taper compensation assemblies 49and 49' may also be manually effected or reset during a manual grindingoperation by means of the RH. com pensation selector switch SS9, and bythe L.H. compensation selector switch SSll, as shown in FIG. 3. Each ofthese switches would provide a signal to the respective AND gates 97 or97'.

It is also to be understood that only a preferred embodiment of theinvention has been specifically illustrated and described, andvariations may be made thereto without departing from the invention, asdefined in the appended claims.

I claim:

I. In a grinding machine for grinding axially spaced workpiece portions[of a workpiece], including a work support for supporting [said] theworkpiece for rotational displacement about the axis of the axiallyspaced portions thereof, [a grinding wheel support including] a spindlefor supporting a grinding apparatus including at least one rotatablymounted grinding wheel, [axially spaced spindle bearings for supportingopposite ends of said grinding wheel spindle,] and means for effecting arelative transverse feeding movement between [said] the grinding wheelspindle and [said] the work [support] piece to perform a grindingoperation on the axially spaced workpiece portions, the improvementcomprising:

[said grinding wheel support includes a cantilever arm] first and secondmeans [at each end] for supporting the opposite ends of said grindingwheel spindle;

means for generating [at least] first and second electrical signals fromfirst and second axially spaced positions on the axially spaced portionsof the workpiece during the grinding cycle, said signals beingrepresentative of the dimension of the workpiece at said first andsecond positions;

means for subjecting either of said first or second supporting means toa deformation force having a selected direction for deforming thecorresponding spindle supporting means whereby the corresponding end ofthe grinding wheel spindle will be displaced towards the workpiece beingground,

means for [directly] compairing said first and second signals and forgenerating a third signal when the difference between said signalsexceeds a predetermined maximum value; and

means actuated by said third signal for [deflecting] actuating the oneof said subjecting means [cantilever arms of the wheel support to move]which will deform the one of said first and second spindle supportingmeans and accordingly displace [the end of said grinding apparatuscorresponding to the higher of said first and second signals] thecorresponding end of said grinding wheel spindle towards the workpiece[to] which will reduce said difierence [bring the grinding wheel spindleinto parallelism with the workpiece].

[2. A grinding machine as recited in claim 1, wherein said deflectingmeans includes two separate force applying mechanisms, one at each endof the wheel support, for moving the grinding wheel spindle toward theworkpiece] 3. A grinding machine as recited in claim 1, wherein [saidplungers have threads at one end, and wherein said force applyingmechanisms] each of said subjecting means [further] comprises:

a hydraulic motor having a piston rod with a rack member formed in theend thereof, said motor being operable in response to said third signal;

a plunger having one end operably engaged with one of said spindlesupporting means and being threaded on the other end;

a pinion nut having internal threads for receiving said one end of saidplunger and having external teeth in mesh with said rack member, andfurther having external threads adjacent [the] said external teeth; and

means in threaded engagement with said external threads of said pinionnut, when the nut is [rotating] rotated by said rack member, foradvancing said nut and plunger toward the one of said [wheel support]spindle supporting means at one rate while said plunger retacts on theinternal threads of said pinion nut at a slower rate, so that saidplunger has an absolute advance [into] against the one of said [wheelsupport] spindle supporting means upon the operation of said hydraulicmotor.

4. In a grinding machine for grinding axially spaced equal diameteredportions of a workpiece, including a work support for supporting [said]the workpiece, a spindle for supporting a grinding apparatus includingat least one rotatably mounted grinding wheel, [axially spaced spindlebearings for supporting opposite ends of said grinding wheel spindle,]feeding means for effecting a relative transverse feeding movementbetween [said] the wheel spindle and [said] the [work support] workpieceto perform a grinding operation, and means for controlling [said] thefeeding means, the improvement comprising:

a grinding wheel spindle support including [a pair of cantilever mountedarms] first and second means for supporting the opposite ends of saidgrinding wheel spindle,

first and second, separate and independently movable, means associatedwith [said cantilever arms of said grinding wheel spindle] each of saidsupporting mearis for deforming said supporting means and for advancingthe [respective ends] corresponding end of said spindle [supports] in aselected transverse direction towards the workpiece during a grindingcycle,

means for gaging the workpiece at axially spaced [axial] positions onsaid portions and for generating signals indicative of the relative sizeof the workpiece at said points; and

means for [directly] comparing said signals and [perable in response tothe gaging means] for generating [another] a third signal whenever therelative size of the workpiece at said two axially spaced positionsvaries more than a predetermined amount, said signal being effective toactuate the one of said [displacing] movable means [to] which will[move] advance the end of said spindle corresponding to the larger sizedworkpiece position toward the workpiece. [until the gaging meansdetermines that the relative sizes of the two positions of the workpieceare within said predetermined amount].

5. A grinding machine as recited in claim 4, wherein each of said[displacing] movable means comprises:

a hydraulic motor having a piston rod with a rack member formed in theend thereof, said motor being operable in response to said third signal;

a plunger having one end associated with one of said first and secondgrinding wheel supporting means and being threaded on the other end;

a pinion nut having internal threads for receiving the threaded end ofsaid plunger and having external teeth in mesh with said rack member,and further having external threads adjacent the external teeth; and

means in threaded engagement with said external threads of said pinionnut, when the nut is rotating by said rack member, for advancing saidnut and plunger toward the one of said first and second wheel supportingmeans at one rate while said plunger retracts on the internal threads ofsaid pinion nut at a slower rate, so that said plunger has an absoluteadvance into said wheel support upon the operation of said hydraulicmotor.

6. A grinding machine as recited in claim 4, wherein said gaging meanscomprises:

transducers positioned at said spaced axial positions for generatingelectrical voltages which are a function of the dimensions of theworkpiece at the respective positions;

and wherein each of said [displacing] movable means further comprises,

a spaced [plungers] plunger for deflecting the end of said grindingwheel support corresponding to the higher of said electrical voltages;and

means, including a hydraulic motor, for advancing [one of] said[plungers] plunger in response to said other signal.

7. A grinding machine as recited in claim 4, wherein, said forceapplying mechanisms include plungers for deflecting one of said armsupon generation of said signal.

8. In a grinding machine for grinding axially spaced pottions of aworkpiece including a work support for supporting said workpiece forrotational displacement about a selected axis thereof, a grinding wheelsupport including a spindle for supporting a grinding apparatusincluding at least one rotatably mounted grinding wheel wherein the axisof the grinding wheel and the selected axis of the workpiece aresubstantially parallel, feeding means for effecting a relativetransverse feeding movement between said wheel spindle and said worksupport to perform a grinding operation, means for controlling saidfeeding means, the improvement comprising:

said grinding wheel support having axially spaced cantilevered portionsextending therefrom to support said spindle;

means for gaging the workpiece at two axially spaced positions [thereof]and for generating at least two electrical signals indicative of theworkpiece diameters at said positions[,] during the grinding cycle;

means for directly comparing said two signals and for generating acompensation signal whenever the signal indicates the axes of thegrinding wheel spindle and workpiece are out of parallelism by more thana predetermined amount; and

force applying means actuated by the generation of said compensationsignal for deflecting the one of the cantilevered portions of said wheelsupport toward the workpiece which will [to] bring the axes of thegrinding wheel spindle and the workpiece into parallelism.

9. A grinding apparatus comprising a pair of elements adapted to berotated about parallel axes,

the first one of said pair of elements comprising a workpiece,

base means,

first and second means for mounting the opposing ends of said workpieceon said base means,

means for rotating said workpiece about the axis of at least a portionthereof,

the second one of said pair of elements comprising a grinding apparatusincluding at least one grinding wheel rotably mounted on a spindle,

first and second means for mounting the opposing ends of said spindle onsaid base means,

means for rotating said grinding wheel about the axis thereof,

means for effecting a relative transverse feeding movement between saidgrinding wheel spindle and said workpiece to perform a grindingoperation on at least a part of said workpiece portion,

first and second means for respectively subjecting the first and thesecond mounting means of one of said pair of elements to a force havinga selected direction for deforming said mounting means and accordinglydisplacing the corresponding end of said one element towards said otherelement,

gaging means for generating first and second signals from first andsecond axially spaced positions on said workpiece part, said signalsbeing representative of the diametral dimension of said workpiece atsaid first and second positions,

means for comparing said first and second signals and when thedifierence between said signals exceeds a predetermined maximumdifierence for actuating the one of said first and second subjectingmeans which will effect the displacement, in said selected direction, ofthe one end of said one element which will result in said diflerencebeing reduced below said maximum difference.

10. A grinding machine according to claim 9, wherein said one elementcomprises said grinding apparatus.

11. A grinding machine according to claim 9, wherein said workpieceportion comprises a plurality of axially spaced diameters.

References Cited The following reference, cited by the Examiner, are ofrecord in the patented file of this patent or the original patent.

UNITED STATES PATENTS 3,064,395 11/1962 Price 51l65 R 3,097,454 7/1963Pheil 51-165 R 3,145,508 8/1964 Price 51-1659 3,271,910 9/1966 Haisch51165 R FOREIGN PATENTS 857,971 1/1961 Great Britain 51-465 R 1,213,45211/1970 Great Britain 51-165 R HAROLD D. WHITEHEAD, Primary ExaminerU.S. Cl. X.R. 51165.91

